The warm up exercises (Warmup Creating Systems) in this Launch section access students' prior knowledge and give me a good picture of student readiness for the activity. I already have a pretty good idea of those students that have struggled more than others throughout the unit.

Today, I want to pair these students up with those that have done well. At first, I tell students to complete the warm up individually. While they are working, I walk around monitoring and helping where necessary and I distribute one card piece (Pair up cards) to each student. The cards were cut out before class and they are ready to be handed to students during the warm up. I distribute the cards strategically so students who may have difficulty with the main activity, are paired with more advanced students to work together.

Once students are finished with the warm-up exercises, I review each question by calling on volunteers to share an answer.

Before asking students to get to work, I project the Burgers image on the board in order to model what each pair of students in class is suppose to do during the activity. The image shows hamburgers and cheeseburgers. I leave the image up for a while and tell the class that I am going to think of a situation which lends itself to writing a system of two linear equations, in order to find the solution to my problem. I then project the model system of equations problem. I call on someone to read the word problem and then ask if they can write the two equations on the board for us. The desired equations are:

b + c = 24

2.5b + 3c = 68

I expect that all of my students will be able to solve this system at this point in the unit. If we're not pressed with time, I may ask the class to solve it and call on someone to write the solution on the board.

I then ask students to stand and go around with their partners, looking at the 6 scenarios posted around the room. I ask that they choose 4 out of the 6 scenarios and use their imagination to...

Create a problem situation from the image

Write the two equations in the system

Solve the system by any method

Some students may want to create their own situation, not a situation in any of the posts. I always allow students to create one of their own if they wish. I also vary the number of problems for students to solve if time runs out.

The students should do all their work on blank sheets of paper (see reflection), one set per group, indicating the scenarios chosen. In order to avoid chaos, I may ask students to choose the images they want to work with and work at their desks. Moving around is always a good idea to help student thinking. I'm flexible enough to allow some groups to sit and work on the floor if they want to. As the class is working, I walk around giving help and guidance, yet allowing each group to create and solve their own problem. Calculators always come in handy here because the values students choose will many times give decimal results when computing results.

Once groups are done with creating their own word problems and solving their systems, I call on volunteers for each of the six scenarios posted, to write and solve their system under the corresponding image. Once all six systems are solved on the board, I call on each group and ask that they state their word problem to the whole class, guide us through the problem explaining what method they used and what the solution to their system equations means with respect to the problem situation.

I ask students to pose any questions after each presentation and allow some time for the students to respond to these. All students should hand in their work containing the four scenarios and solved systems, before leaving the class.

Student sample work (see Successful Scenarios in the Lesson reflection for more about how students worked on these tasks):